List of Figures
1.1 Relative conversion of NO within 5 ms based on its total formation
[18] . . . 10
1.2 Principles of Air Staging (A) and Fuel Staging (B) . . . 13
1.3 External flue gas recirculation system [21] . . . 15
1.4 Axial confined jet and secondary recirculation [21] . . . 15
1.5 Creation of a central toroidal recirculation zone resulting from swirl [21] . . . 15
1.6 Recirculation by means of a bluff body [22] . . . 15
1.7 Flammability limits for methane-air mixture [26] . . . 16
1.8 Stability diagram for methane-air combustion [23] . . . 17
1.9 Idealized flameless oxidation [23] . . . 18
1.10 Experimental apparatus used by Wünning and Wünning [23] . . . . 18
1.11 FLOX®recuperative burner [23] . . . 19
1.12 Time resolved temperature measurement for flame, unstable and flameless regime [23] . . . 19
2.1 (a) Jet in Hot Coflow burner [35] and (b) computational domain [40] 23 2.2 NO Rate of production analysis (ROPA) for Glarborg (a) and POLIMI (b) mechanism. Blue lines indicate NO destruction, while the red ones NO formation. . . 26
2.3 Computational domain, mesh grid and boundary conditions [40] . . 29
2.4 Comparison between measured and predicted radial profiles of NO, in constant (a-c-e) and experimental profile (b-d-f) boundary con-ditions for flame HM1. . . 33
2.5 Comparison between measured and predicted radial profiles of NO, in constant (a-c-e) and experimental profile (b-d-f) boundary con-ditions for flame HM2. . . 34
2.6 Comparison between measured and predicted radial profiles of NO for flame HM3. . . 35
List of Figures
2.7 Relative importance of NO formation routes for flame HM1 . . . 36
2.8 Relative importance of NO formation routes for flame HM2. . . 36
2.9 Relative importance of NO formation routes for flame HM3. . . 36
3.1 Scheme and characteristics of IPFR facility . . . 38
3.2 Weight loss curve during the thermogravimetric analysis . . . 39
3.3 Gas pre-heating section . . . 40
3.4 Gas pre-heating section 2 . . . 41
3.5 Air collector, external (a) and internal (b) view. . . 42
3.6 Swirl system, fixed (a) and moving (b) parts. . . 42
3.7 Burner body (a-b) and Combustion chamber side (c). . . 43
3.8 Axial (a) and radial (b) probe. . . 44
3.9 Radial temperature profile at x = 122 mm . . . 45
3.10 Measurement points . . . 46
3.11 NH3 solution and natural gas feeding probe . . . 46
3.12 Sampling system [49] . . . 47
3.13 Scheme of the sampling probe [49] . . . 47
3.14 Basic component of a FTIR spectrometer [49] . . . 48
3.15 Michelson interferometer [49] . . . 48
3.16 Example of multi-component analysis [49] . . . 50
3.17 Swirl geometry . . . 52
3.18 Burner geometry . . . 52
3.19 Swirl domain grid . . . 53
3.20 Burner domain, grid 800k cells . . . 54
3.21 Contours of Temperature (800k cells) . . . 55
3.22 Burner domain, grid 1.900k cells . . . 56
3.23 NO Rate of production analysis (ROPA). Blue lines indicate NO destruction, while the red ones NO formation . . . 61
3.24 (a) Pathlines along the swirl duct, coloured by velocity magnitude (m/s). Contours of Radial (b) and Axial (c) velocity (m/s) at the swirl exit. k-✏ realizable turbulence model. . . 65
3.25 Radial profiles of temperature at x = 122 mm predicted by ED/FR with global chemistry, EDC with global chemistry and EDC with Kee. k-✏ realizable turbulence model. . . 66
3.26 Temperature (K) and Axial velocity (m/s) distribution predicted by (a-b) ED/FR with global chemistry, (c-d) EDC with global chem-istry and (e-f) EDC with Kee. k-✏ realizable turbulence model. . . . 67
List of Figures
3.27 Radial profiles of temperature at x = 122 mm predicted by k-!, k-! SST and k-✏ realizable. Kee kinetic mechanism. . . 68 3.28 Temperature (K) and Axial velocity (m/s) distribution predicted
by (a-b) k-!, (c-d) k-! SST and (e-f) k-✏ realizable. Kee kinetic mechanism. . . 69 3.29 Radial profiles of temperature at x = 122 mm predicted by k-! and
k-! SST. GRI 3.0 kinetic mechanism. . . 70 3.30 Temperature (K) and Axial velocity (m/s) distribution predicted by
(a-b) k-! and (c-d) k-! SST. GRI 3.0 kinetic mechanism. . . 70 3.31 Predicted and measured CO concentration in three different points. 71 3.32 Predicted and measured C2H4 concentration in three different points. 71
3.33 Predicted and measured NO concentration in three different points. 72 3.34 Relative importance of NO formation routes in case of no ammonia
injection. . . 72 3.35 Predicted and measured NO2 concentration in three different points. 73
3.36 Predicted and measured N2O concentration in three different points. 73
3.37 Predicted and measured NH3 concentration in three different points. 74
List of Tables
1.1 Reaction parameters for Zeldovich and N2O intermediate
mecha-nism. Units: mol, cm, s, K . . . 5
1.2 Reaction parameters Prompt mechanism. Units: s, K . . . 7
1.3 PFR Löffler Condition. . . 10
1.4 Kinetic parameters applied to Löffler model [18] Units: mol, cm, s, K 12 2.1 Operating conditions for cases studied (compositions are as mass fractions)[40] . . . 24
2.2 PSR operating conditions (compositions are as mass fractions of the total inlet stream) . . . 25
2.3 Details of the numerical simulations for NO evaluation in JHC burner 31 2.4 Predicted NO emissions with different models for different flame . . 31
3.1 Combustion Conditions . . . 42
3.2 Natural Gas Composition, expressed as volume fraction. . . 44
3.3 Summary of the experimental campaign n.2 [49] . . . 46
3.4 PSR operating conditions . . . 60
3.5 Details of the numerical simulations for experimental campaign n.1 64 3.6 Details of the numerical simulations for experimental campaign n.2 64 B.1 Kinetic parameters applied to New model in JHC conditions, using Glarborg [19] detailed kinetic scheme. Units: mol, cm, s, cal . . . . 78
B.2 Kinetic parameters applied to New model in JHC conditions, using POLIMI [41] detailed kinetic scheme. Units: mol, cm, s, cal . . . . 80
C.1 Kinetic parameters applied to New model in pilot-scale burner con-ditions, using Glarborg [19] detailed kinetic scheme. Units: mol, cm, s, cal . . . 82
